Roaches in California

© D. Kucharski K. Kucharska/

Written by Taiwo Victor

Updated: April 11, 2022

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Roaches are nocturnal insects of the order Blattodea. Of the over 4,600 species of roaches in the world, about 30 species are associated with human habitat and regarded as pests. The rest are considered beneficial or harmless in their natural environment. Nearly 55 different types of cockroaches are found in the United States, making up only 1.5% of cockroach species in the world. However, five of these cockroach species are commonly regarded as pests in California. They are — German cockroach, American cockroach, brown-banded cockroach, oriental cockroach, and Turkestan cockroaches. Although the biggest threat and the one most commonly encountered by homeowners battling an infestation is the German cockroach, you will typically find that all five cockroach species are significant year-round household pests in California.  

In this article, we’ll take a closer look at the common species of roaches in California, where you can find them, and how you can identify them. Then, we’ll discuss which seasons roaches are more active and how to get rid of them from your home. Finally, we’ll be answering the popular question on the minds of most California residents – how common are roaches in California? Let’s dive in!

Common Species of Roaches in California

California is home to five species of cockroaches that are commonly regarded as domestic pests: German cockroach, brown-banded cockroach, oriental cockroach, American cockroach, and Turkestan cockroach. Each species has its unique characteristics.

German Cockroach

German Cockroach

The most persistent cockroach species is the German cockroach.

©7th Son Studio/

The German cockroach is considered the most troublesome and persistent of all the indoor cockroach species in California. They are light brown or tan, with the female darker than the male. They live and breed in warm, humid, and dark areas, occupying tight spaces around sinks and in the walls. Found invading most structures, especially near food preparation and storage areas, the German cockroach is the most commonly seen indoor cockroach in the world. Not surprising since they reproduce and spread rapidly — a single female German cockroach can start a breeding explosion of up to 30,000 roaches in a single year!

American Cockroach 

American cockroach on wood

American cockroaches are the largest roaches in California.


The American cockroach is the largest of all house-infesting roaches in California (and in the United States), measuring on average 4 cm (1.6 inches) in length. This huge roach is active all year round in warm and moist locations in homes and apartments and can be easily identified by its reddish-brown appearance. The American cockroach produces odorous secretions, which can alter the flavor of food, and if they’re present in a high population, you’ll be able to smell them. They are also considered one of the fastest running insects, darting out of sight at the slightest threat. At 50 body lengths per second, the American cockroach is about three times the speed of a cheetah!

Oriental Cockroach 

Black Cockroach - Oriental Cockroach

Sometimes referred to as water bugs, oriental cockroaches have a shiny dark appearance.


The oriental cockroach is sometimes referred to as a water bug or black beetle because they prefer to live in damp or moist areas, and their bodies have a shiny dark appearance. You’ll often find this roach species in sewers, drains, damp basements, porches, and any other damp areas in households. They have a strong smell and are considered one of the dirtiest roaches in California. They are known to spread dysentery, E.coli, Salmonella, and food poisoning and are often harder to get rid of than the other cockroaches. 

Brown-banded cockroach 

๋Juvenile brown banded cockroach isolated on white floor.

The smallest species of cockroach is the brown-banded cockroach.

©Chumrit Tejasen/

The brown-banded cockroach is tan to light brown and has two light-colored bands across its wings and abdomen (hence its name). It is the smallest cockroach species in California, measuring about 10 to 14 mm (0.39 to 0.55 in) long. Interestingly, you can find this small domestic roach in open places such as living rooms and bedrooms (because they need less moisture than the other types of cockroaches). They avoid light, so they are more active at night.

Turkestan Cockroach

©D. Kucharski K. Kucharska/

The Turkestan cockroach (also called ‘rusty red cockroach’) is the most recent cockroach species in California. Female Turkestan cockroaches are dark-brown to black with lighter stripes, while males are red or orange-brown. They are primarily outdoor pests usually found in leaf litters, cracks between concrete, compost piles, potted plants, and sewer systems. But they often invade buildings in search of a cooler (preferably, damp) spot indoors. Turkestan cockroaches are unfortunately a growing problem in and around California homes.

Do Roaches Fly in California?

The sight of a cockroach flying has a lot of people running for cover. The good news is that out of over 4000 different species of roaches in the world, only a handful of cockroaches can fly. These include cockroaches such as Pennsylvania wood cockroach, Smokybrown cockroach, Cuban cockroach, and a few other species that have wings long enough and developed enough to sustain flight. 

Within the Californian cockroach population, the American cockroach is a roach species that can fly with its body-length wings. The male Turkestan roach and the male brown-banded roach (females of both species are wingless) have long wings for flying. However, these cockroaches are weak fliers and prefer to glide with their wings. On the other hand, the oriental cockroach can’t fly because it has underdeveloped wings, while the German cockroach has wings but doesn’t use them to fly at all. No matter the species, all baby cockroaches (also called nymphs) are wingless.

How Common are Roaches in California?

There’s a growing increase in the number of roaches across California. Homeowners are constantly faced with the challenge of dealing with cockroach infestations in their homes, garages, and yards. What makes California so widely invaded by roaches?

A report from Rich Sartain, a pest control expert, explained that the rising temperatures and drought conditions in the region are driving roaches that typically live in sewer systems to start making their way into homes. Interestingly, it is also believed that the relatively new Turkestan cockroach has contributed massively to the increasing population of roaches in California. It’s probably best to do everything you can to keep these unwanted pests out of your home and your yard.

What Season are Roaches Most Active in California?

Unlike many pests who have seasonal surges, roaches are ubiquitous pests. They can thrive in a wide range of environments. That is to say, every season is roach season. The warm moist spring and summer seasons are especially their favorite time for foraging and breeding. This means that in states with warmer climates, such as California, there’s no off-season for roaches. Cockroaches are active in spring when it’s hot and also in fall when organic matter is decaying – because they’re attracted to such conditions. Even though their population numbers are smaller during the cold winter months, they do not go away; they simply find means to get inside your homes and buildings to hibernate. There’s no avoiding them in any season — these persistent little critters are active all year round!

How Do You Get Rid of Roaches in California?

If you’ve ever had to deal with an indoor infestation of cockroaches, you can agree that cockroaches are stubborn and resilient pests. A rule of thumb for roaches says that for every roach you can see, there are a dozen or more you can’t see. Even though getting rid of cockroaches completely may be challenging, there are easy ways to try. But to successfully kick cockroaches out of your home, you first have to identify the species of roach you’re dealing with and where they are hiding in your home. Then, you can choose one or more of the following control methods to get rid of these roaches; 

  • Boric acid powder
  • Borax
  • Bait stations
  • Diatomaceous earth 
  • Bait traps 
  • Gel baits 
  • Silica aerogel
  • Insecticidal sprays 

Unfortunately, pesticides alone are not enough to solve a cockroach-infestation problem. You must adopt proper sanitary measures to prevent future infestation. Because roaches thrive where food and water are available to them, it is important to keep your kitchen clean. Store your food in airtight containers and keep all trash cans away. Besides, try to block their access to your home by sealing off the common entry and hiding areas such as cracks or holes. If you have a serious cockroach infestation problem that is out of your control, you may need to contact professional pest control services.

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About the Author

For six years, I have worked as a professional writer and editor for books, blogs, and websites, with a particular focus on animals, tech, and finance. When I'm not working, I enjoy playing video games with friends.

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